Method of mounting diaphragms in sound-boxes.



P. ODGE. METHOD or Mournm DIAPHRAGMS 1N souNo oxEs'.

Patented Feb, 13, 1917.

UNITED STATES PATENT OFFICE.

PARKER DODGE, OF WASHINGTON, DISTRICT OF COLUMBIA.

METHOD OF MOUNTING DIAPHRAGMS IN SOUND-BOXES.

Application led May 18, 1915.

1 o all wlw/ml it 1n {1. 1/ concern:

Be it known that l. lamum Donfut, a citizen of the llnited States. residing at lVashington. in the District ot' Columbia. have invented certain new and uset'ul Improvements in Methods ol" Mounting Diaphragms in Sound-Boxes. o'l which the 'following is aspecification.

This invention relates to sound boxes for gramophones, graphophones and they like, and particularly to a method oi' mounting the diaphragm under a uniformly distributed radial compressive stress. to render the diaphragm relatively inert1 to increase its freedom of vibration and to secure other incidental advantages.

I shall describe the method as applied t0 a sound box in which it secures peculiarly pro nounced beneficial results, that being the sound box having conoidally recessed diaphragmclamping means described and claimed in my prior application for patent, Serial Number 12,578, filed March 6, 1915. In another copending application, Serial Number 2H,9l1 tiled hlay 1S, 1915, I describe and claim a Sound box ha .fing a diaphragm held under a radial compressive stress. The

presenty application is accordingly restricted v to the preferred method oi placing and maintaining a diaphragm under such stress.

In the accompanying drawing- Figure l is a front elevation o't' a sound box in assembling which my present method may be practised;

Fig. 2 is an axial section thereof;

Fig. 3 is a perspective view of a clamping ringused in such sound box;

1 `ig. 4 consists of four cross sectional diagrams illustrating four successive steps in the method of mounting the diaphragm, only the diaphragm and clamping rings being shown; and

Fig. 5 is a 'face view of a diaph 'agm with the stresses to which it is finally subjected diagrammatieally indicated.

In the drawings 6 represents the usual rubber connector sleeve for connecting the sound box or reproducer to the goose neck or tone arm of the machine on which it is to be used. The sleeve has the usual brass Specification of Letters Patent.

raient-ed non. 13, 1917.

Serial No. 28,910.

lining tube 7 which fits over the end ot the goose neck. and is provided with the usual bayonet lock pin (not shown). The cupshaped body 9 ot the sound box, which is ot metal. is held to the connector sleeve G by means of screws l0 and by means of a metal weight ring 1l which closely embraces the Sleeve 3 and is sealed to the rear Atace of the box-body 9 witlra thin layer oi bees-wax or similar plastic adhesive l2. rlhe purpose oi this weight is to dairp any vibrations which might be set up in the box-body il.

The box-body 9 is internally threaded as indicated at l'l and is provided with an aperture 14 leading through connector sleeve G to the goose neckor tone arm.

The, diaphragm 15 which preferably is of mica is clamped between two rings 1G and 17 of substantially identical form.y each having a central aperture which l prefer to make ot substantially the size ot aperture 14. The face ot each of. the rings 1G and 17 toward the diaphragm is a surface of revolution. The generating curve is tangent or approximately tangent to the conta. :ting face of the diaphragm at or near its periphery and curves gradually away trom such face toward the center ot the diaphragm. The clearance between the opposed 'faces of tiny rings 1G and 17 need be only slight" greater than the maximum amplitude of vibration ot the diaphragm and is somewhat exaggerated in the drawing. The rings 16 and 17 may be of any relatively rigid material` The best results have been secured with Celluloid but successful use has been `made of metals, for example aluminum and brass. The brilliancy oi tone seems to increase with the hardness of the material used for the rings.

The rear ring 16 is sealed to the, r ear Wall of the, box body by a thin layer 18 of beesv wax or similar adhesive plastic and the, iront ring 17 is pressed toward it by a nut ring 19. Paper gaskets QOmay be interposed between front ring 17 and nut ring 19, partly to equalize the pressure by their resiliency and partly to permit nut ring 19 to turn more freely on ring 17 in assembling the soundbox.

threaded ellis 21:. il' has the usual neeille socket in which needles may he lampe-il by he sel: screw The stylus arm 2l is connected io the een ,i oi the diaphragm i5 hy means of a Lire-ai v sind i?" :incl nut 2?', the usual washers i353 ing used 13o (lisvrilmle 'the pressure The sound box so far ileseii'heil is ghei Claimed iii my application Fie l.al No.' l l have discovered tha the Lone quality cured wili such a souiiil hex, and so e iaixi exten'e with any sound, hoi: havin?- a, rigid iliapliragni-moon@` is iiiiprmf'eil, mounting: Lilie f liaphragin umler a radial acting compressive stress.

To secure his result l may proc lows: l rst loosely assemble Joe if i5, rings ll' and l?, .aus ring l) ano i"- 20 iii the hoi; holly llhisieonfiiizn resented iii the first diagram oi where the small force arrows represen i light clamping pressure on rings 1G and fifi merely suifiieien io hold the parts sieg e The second step is to deflect the diaphragm l5 ai; leheeen'ier hy a pressure erted manually or by means oi a clamp.

This eoniructs sl'htly the periphery diaphragm l5, This condition is illussraiecl in the second diagram of Fig. i where `the arrow Z) represents the deileerting The third Siep is to set down 'the nui r" 4 i9 tight while holding the diaphragm i5 deiected. riliis condition is illusiateil in the third diagram of Fig. where the arrows A represent the heavy elanii'iine; pressure resulting from setting down the iut ring lbf).

rl`he fourth step is to relieve the iliaphragm from the deleeting stress oliereupon it returns to the coudiioii illustrated in the fourh diagram of Fig. liere the heavy clamping pressure represented. hy the arrows .Iii prevents the expansion oi' the periirihery of the diaphragm so tha flche diaphragm remziins under :i uniformly clisirilou'teii compressive siress as iudieaied in cli. in Fie'. in Fig. 5 the arrows meent to illusirate a uniformly distrihuefl. r dially acting stress and noi', a laraliy of localized substantially equi Yaieiib method.

clamp the diaphragm with zi Very moileroe clamping pressm"l and 'then ruil @he soulful box on a number of very heavy or lon/ci reeords and thea iiinrieifliately clamp alia pl'iragghi 'Very Light ehe c or meile ato clamping' pressure is serre/J5 ii; will mit tl .e eeriiihery o. in or contrari' under lle so.. vibration. ie er-:pazisive 1i diaphragm will nel: however h( s overa ome the ilirieiioii of i possiomj ye y slewiy7 eno ,1: e enige of 'the liaghi'agn hus holds; his eoaeraeied. lioth niehoils have in common ii-he idea oi' coiiiraetion, he periphery hy il the cellier, and oi' final clamp" 's contraction exists,

ed is charaeieri.

essing increases ihe loneliness sound secured m i'eproihio 'ihe iicir se@ eiziveness in'iirofiuees some munies? hoi suoli diaphragme een. be used with iiiailiei'l success, o'e Kamp in he pai-tieni `L .io of :Bound hoi; with which have 'il Il i' l ,l;. 'lavinfg' i" i elaiih ii L The iiiehoii of morini" sound-hors :viii-,l :iho 'i prode/i eonirzn `Vo ragni hy die f e diaphragm, and

,id periphery' while ,The :meihoci o mounting' iliaphragins he like, which coniii 'placing @he diaphragm between a pair of clamping members adapi'ml io engage opposite faces al; er near its periphery, producing a contraction of saisi p l riphery hy deliee'iin he central portion of said diaphragm, z 'hen said clamping members together no clamp said diaphragm positively hew'een heni Whiie iles periphery' eonliracted.

25. The method olimountmg' diaphimgfis in sound-boxes and the like which consists in (le'ee'iiig the ceniral portion of the im phrogm 'to contract the periphery J@hereof anfl hen While inainsaining said (leieeziou positively eiaiziping said contracted periph` honi of mouniing iliziphraffms i L '2.7 wares and Ehe like which eonsiss in ie diaphragm between. :i pair of iiieinhers adapted io en age i'is iaees at or neer its periphery, oe he central portion oi said. phregm to cohlraci; its periphery', lgheii while axaiiiaining said deieetion, clamping; said` iiaphro bewees. said clamping; members, and. theo relieving saidv iliapliraga'N from the.

e siress.

(liaer maintaining a positive pe;

iii senin-acting the said contraction by the action of a rigid diaphragm mount. cnguging the peripheral. portion o f Suid diaphragm.

7. Tho mcthod of mounting;r acoustic din-- 5 phrugms which consists in placing a diaphragm in Contact with :i rigid diaphragm mount; applying u distorting agency to caiubc the linol of contacty between thc mount PARKER DODGE. 

